EVOLUTION OF THE SKULL AND TEETH OF EOCENE TITANOTHERES 



265 



Brachycephalic types. — In the short-skuUed Palaeo- 

 syops we observe heavy canine tusks, large canini- 

 form outer incisor teeth, deep and heavy zygomatic 

 arches and lower jaw, high and relatively thin sagittal 



for plucking and tearing up succulent bulbs, tubers, 

 and roots from the ground as well as for browsing on 

 twigs and leaves, a diet much in favor with the Amer- 

 ican tapir. But it differed from the tapir in that the 



£o tita n ops 



' A^anteocercLS 



Figure 219. — Skulls of Eocene titanotheres of the principal genera 



Side views. One-eighth natural size. A, Eotitanops borealis, lower Eocene, Wind River formation; B, Limnoliyops prisms, middle Eocene, 

 Bridger formation, horizon Bridger B; C, Palaeosyops leidyi, middle Eocene, Bridger formation, horizon Bridger D; D, Telmatherium 

 uHimum, upper Eocene, Uinta formation (Uinta C); E, Manteoceras manieoceras, middle Eocene, Bridger formation, horizon Bridger 

 D; F, Mesatirhinus petersoni, middle Eocene, Bridger formation, horizon Bridger D; G, Meiarhinus earlei, upper Eocene of Uinta 

 Basin, level Uinta B 1; H, DolichorUnus hyognathus, upper Eocene of Uinta Basin, level Uinta B 2. H, Horn. 



crest, and large areas of attachment for the temporal 

 and masseter muscles. This indicates a notably ver- 

 tical movement of the jaw and great power in crush- 

 ing the food. Such an animal would seem well fitted 

 101959— 29— VOL 1 20 



nasals are not retracted, and there is no evidence that 

 the upper lip had exceptional prehensile power. (See 

 fig. 220.) This titanothere presented the extreme of 

 the browsing type. It had a lumbering gait and 



